Rotary tiller



L. DUFOUR ROTARY TILLER Jan.

Fil'ed Aug. 12, 19:51

Patented Jan.- 5, 1932 I r 1,840,188

UNITED STATES PATENT OFFICE neon nuroua, or vnasoix, nun sum. swrrznanmn sonar p i Application ma Au 12, mi, Serial 30,550,039, and man-many gm i4, am. In rotary tillers with resilientl yielding Figure 4 represents an embodimentwith' tines it is known to obtainthe esired ,refiat steel springs; l

silienc by using as stems for the actual time Figure 5 isa' detail view of a, device'for.fas-- woun springs which .arearranged or dis-i teningthe'tines tosuch flat springs;

o. tributed around thedrivingshaftr i Fi 6 and .7 show an alternative form 85 v The present invention relates to a rotary for e tools; 7 1 j tiller with tines secured upon the driving Figure 8sho'ws a'diametrical-arrangement shaft by intervening helical or's iral rings of tines; 9

wound around the driving sha itsel hav Figure 9 showsa method of fastening sev Q 9 ing referab ly their turns side by side, in eralsymmetrical-double sprin on the shaft. to

whic the sp'mgs are so arranged on" the F lfiure 10 is a detail view 0 the fastening shaft, that during normal workin their inof'fla springs. 1'

ner surface is not a lied to the wit when In Figures I 2 and 3=which illustrate one theyyield backwarsiy during the bite, but such construction, around steel spring b if the normal resistance is exceeded, they as so wound around the driving shaft 0 with *66 yield backwardly and inwardly and wind its turns side by side that when stressed by close upon the shaft (which isnot necessarily normal working the greater part of its round) as a 4 safeguard against breakage. springy lengthstands away from the shaft, Further defor'mationof the sp by distor and only when the tool encounters some untion in the direction of' the p di l io stones,' usual resistance in the earth does the spring I j roots or like) is thus made impossible, while windelose u n -the shaft'a so as not to he the arm at which the resulting bending 'mo- 'deformedand so as simultaneously to shorten ment acts is substantially dimmishedso eonthe arm at which thefben moment then 1 siderably relieving the springs. h applied-to thetool acts. T e sprin 'b is With'thjs construction the yield rearward 4 constructed in known manner, as a ouble I with respect to the direction of out may be spring with its two parts mutually inclined kept verygreat while the inward yield may or symmetrical] wound from the centre out smaller than when the center of rotation ward to veach si e. At the ends 6 2g which of the spring is outside'the sha the double spring is fastenedto the aft, re

By winding the springs around "the driv ,cesses (rare formed insaid ends whiehenable ing shaft andso dispensing withieccentricalthese ends to be sprung by great axial'p'resarranged linlr'springs so much room is set sure under low hooks YPIOJGCti-Hi from the as for enlarging the working hook or tine shaft. No further fastening of t e1 spri a that for a "yen s of out, the' bite is ac is necessary. The double sprin 'eompanied y less urrowing and at moderate passed over the shaft from one end nd orer speeds of out a larger bite can be taken than the hooks d, ifits' roportions and its mateotliervvrise. By this. means coarser bleakin rial are. suitably c os'en sothat the radial up of the earth is obtained'suitable to; fiel play between the shaft and the turns of-the cultivation as distinct from garden cultiva--- spring is ter than the radial projec ion tion. oftheho'o s f l In the accompanying drawings various ex- The claws ipf roundsteel may be com I a nples of constructionacco tothe inven-' nected with such d uble sp' of known tion are illustrated emdployingm some cases patterns after the fashion oi iffiot and the u'nd steel sprlngsan in others flat s rings. claws maybe either simple-or forked. For

" f 'lliigure 1 is'a partial cross seetiont ugh thispurpos'e in eithercase the end of the em odim n wi h und steel springs claw i-to be attached to the stem is formed ows atdetail section 'on line into a loo 1?? which is laid flat a ainst the 'A-.- of-l51gture 1; I eorrespomhnglyloopedlimb b'oft'edouble f F r 8 shows a ongitudinal section on spring... A key m'isf through the, 5 line. big el; 4

theym surrounded and heIZTfto-T "9*" which it is wound and notwithstanding its To we the claws and springs yet greater inwar yield before the latter become applied to the shaft, the springs may be wound of flat steel, which, owing to the form in greater width, allows considerable lateral yield in addition'to rearward and inward yield so that the claws can be deflected laterally b'y stones. These flat springs also permit the very simple arrangement of several tines in one and the same plane transverse to the shaft. Such a construction is shown in Fi re 4 where the flat springs b have at their inner ends claws b en'ga 'ng in longitudinal slots 0 in the shaft a. hey may conveniently be held down upon the shaft by hooks 'd bein reinforced if desired as shown in Figure 10 y a blade which has edge ribs enga g beneath the ooks. The s rin are t us rotected against twisting an ben ing at t e point of fastening, and also are interchangeable with the round steel springs of Figures 1, 2 and 3. e

If two (or more) flat springs are used in the same transverse plane, as in this instance,

the spirals of several turns are so interleaved that when one tool yields rearwardly and its spring yields rearwardly and inwardly it comes upon and transfers some stress to the next spring. Thus the spin s of the tines which are not at the moment iting are also stressed and in an extreme case will all wrap themselves close upon the shaft and so preserve themselves from fracture.

The connectionbetween the flat springs and the claws i is preferablymade by means of a wedge lock 8 (Figure 5). The root i of the claw i is formed into a loop and placed on the inner side of the outer end of the spring between converging retainin flanges 5 formed upon the spring. Into t ese the loop 11 wedges and the workin pressure tends to secure it more firmly in p ace. This connection may be used for both simple and forked claws. While in the construction above described the actual tool consists of a claw or bent hook laterally bent flat steel claws j mabe used instead. Such claws are shown in igures 6 and 7 and the are better than the usual forwardly bent c aws for cutting off weeds and stubble and when theyare inclined backward t eir cutting edges are not so much caught up asthe other claws by roots or stones, nor do they collectlweedsso much. To fasten suchclaws upon the flat springs the outer ends of the rings are bent to form a shortclaw 6 like t at at their inner ends,

' sprun over the snaps down upon the claw end 0 the spring and is prevented b a shoulder or like projection from pushing urther along the spring.

If it is desired when using round steel s iral springs to place two claws not one beside the other but about 180 apart without interleaving the springs, a single spring may be prolonged in-an arc of about 180 beyond the point at which its tool is fastened to it. This is shown in Figure 8. A fastening t intermediate in the length of the spring attaches one tool and a similar fastening t at its end attaches the other.

Figure 9 shows a way of fastening several s mmetrical double 8 rings upon the driving s aft a so that the c aws are sta gered circumferentiall by about'180". he fastening is effects by means of bushes u keyed upon the shaft a, at one end with two oppositely directed hooks d The ends of sec double spring are enaged by the hooks of two neig bourin ushes u, so that for instance the left han end of the left hand sprin in Figure 9 is enaged in the hook of the eft hand bush and its right hand end, in the lower hook of the" 9 next ush, the upfierhook of which serves for fastening the le hand end of the second spring, and so on. This method of fastening by means of separate bushes facilitates the mountin of the springs upon the shaft.

What claim is:

y 1. A rotary tiller comprising a driving shaft, working tines and springs securing the working tines to the drivin shaft, said springs being wound aroun the driving s aft itself and being so formed relatively th the same that under the normal workin stresses the greater part of the resilient length of, the turns of the s rings stands out from the shaft ermitting e tool to yield rearwardly, whi e when an abnormal resistance is encountered in the ground the'sprin wind close upon the circular or other sha t and diminish the arm at which the to the driving shaft, said e.

each of which is provided stresses thegreater part of the resilient length of the turns of the springs stands out from the shaft permitting the tool to yield rearwardly, while when an abnormal resistshoe is encountered in the ground the springs wind closeupon the circular or other shaft, said springs consisting of symmetrical double springs of round steel having their ends sprung under hooks upon the shaft and ryin the tines in circumferentially stagbeing recessed to engage upon said hooks.

3. A rotary tiller comprising a driving ere position, the end of each spring being astened by hooks formed on two neighbourshaft, working tines and springs securing the ing bushes fixed upon the shaft.

working tines to the driving shaft, said 11 witness whereof I have hereunto signed springs being wound around the driving shaft my name this 3rd day of August, 1931.

itself and being so formed relatively to the same that under the normal working stresses the greater part of the resilient length of the turns of the springs stands out from the shaft permitting the tool to yield rearwardly, while when an abnormal resistance is .en-

countered in the ground the springs wind close upon the circular or other shaft, said .springs having their turns lying side by side.

means of loops formed on the spring and tool which are' coupled by a ke{ passing through them and held together rounding resilient casing.

5. A rotary tiller comprising a driving shaft working tines and springs securing the worklng tines to the driving shaft, said springs being wound around the driving s aft itself and being so formed relatively to the same that under the normal working stresses the greater part of the resilient length of the turns of the springs stands out from the shaft ermitting the tool to yield rearwardly, whie when an abnormal resistance is encountered in the ound the spr' 8 wind close upon the oircuar or other sha said springs consisting of fiat steel rings 1 having at their outer endconvergi anges, whilst the tines are provided at t ir root with a wedge shaped end arranged to wedge t e symmetrical double spr' working tines to the drivin between said converging flanges of sprin 6. i rotary tiller comprising a driving shaft, working tines and springs securing the shaft, said sprin being wound aroun the driving shaft itself and being so formed relatively to the same that under the normal working stresses the greater part of the resilient length of the turns of the springs stands out from the shaft permitting the tool to yield rearwardly, while when an abnormal resistance is encountered in the and the sprin wind close upon the cirou r or other sh said springs being constituted by several side the other on the shaft and caround the sprin sy -a surseeured one be- 7 Leon DUFOUR. 

